Description

The ignition system is a breakerless inductive discharge ignition system. It has two circuits, the primary circuit and the secondary circuit. The primary circuit consists of the battery, switch, primary coil winding, computerized ignition timer and associated wiring. The secondary circuit consists of the secondary coil, the spark plugs and associated wiring.

The computerized ignition system consists of two assemblies, the rotor and sensor plate and the computer microprocessor module. The rotor and sensor plate are located in the gearcase cover on the right side of the motorcycle. The computer module is mounted above the regulator at the front of the frame. The computer has two functions. First, it opens and closes the low voltage circuits between the battery and ignition coil to produce high voltage discharge to the spark plugs. Second, it computes the spark advance for proper ignition firing.

1. Sensor plate

2. Computerized control module

3. Ignition switch

4. Battery

5. Ignition coil

6. Spark plug

7. Main circuit breaker

8. Ignition circuit breaker

9. Engine stop switch 10. Rotor

Figure 5-23A. Ignition System Components

1. Sensor plate

2. Computerized control module

3. Ignition switch

4. Battery

5. Ignition coil

6. Spark plug

7. Main circuit breaker

8. Ignition circuit breaker

9. Engine stop switch 10. Rotor

Figure 5-23A. Ignition System Components

The ignition timer includes a rotor, sensor plate, and a computerized microprocessor control module. A single ignition coil fires both spark plugs at the same time, but one spark occurs in the exhaust stroke of one cylinder, while the other spark fires the combustible gases in the other cylinder to produce the power stroke.

The rotor is bolted on to the camshaft and operates at one-half crankshaft speed. The computer module automatically advances the spark as the engine speed increases, and retards as the speed decreases without the action of flyweights, or an advance mechanism. This ensures correct spark timing to suit starting, low and high speed requirements.

As the rotor turns, slots in its external edge break the magnetic field to a Hall-effect device mounted on the sensor plate. The output of the Hall-effect device is a logic-type signal that corresponds to the timing information from the spinning rotor. This technique gives accurate timing information down to "0" speed.

Basically, the system gives a spark near top dead center for starting, and at rpm's above this gives a spark advance somewhere between 3° and 35°. The whole timing program can be shifted by mechanical rotation of the sensor plate. See CHECKING ADVANCE TIMING WITH STROBE TIMING LIGHT and SETTING RETARDED TIMING.

The computerized control module contains all of the solid state components used in the ignition system. The dwell time for the ignition coil is also calculated in the microprocessor and is dependent upon engine speed. The programmed dwell is an added feature to keep battery drain to a minimum and yet gives adequate spark voltages at all speeds. (The microprocessor control module has added protection against transient voltages, continuous reverse voltage protection, and damage due to jump starts.) The system will operate down to 5.7 volts DC. The control module is fully enclosed in a polyurethane material to protect it from vibration, dust, water or oil. This unit is a non-repairable item. If it fails, it must be replaced.

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